Ray optics practice · Mixed difficulty

${f_v}$ and ${f_r}$ are the focal lengths of a convex lens for violet and red light respectively and ${F_v}$ and ${F_r}$ are the focal lengths of a concave lens for violet and red light respectively, then

A man can see the object between $15\,\,cm$ and $30\,\,cm$. He uses the lens to see the far objects. Then due to the lens used, the near point will be at

For total internal reflection to take place, the angle of incidence i and the refractive index $\mu$ of the medium must satisfy the inequality

A plane mirror produces a magnification of

What is the refractive index of material of plano convex lens. If radius of curvature of the convex surface is 20 cm and focal length of the lens is 30 cm

Statement-A: Image formed by concave lens is not always virtual.

Statement-B : Image formed by a lens is real if the image is formed in the direction of ray of light with respect to the lens.

A telescope consists of two lenses of focal length $10 \mathrm{~cm}$ and $1 \mathrm{~cm}$. The length of the telescope when an object is kept at a distance of $60 \mathrm{~cm}$ from the objective and the final image is formed at least distant of distinct vision is

A microscope is focused on a coin lying at the bottom of a beaker. The microscope is now raised up by $1\,\,cm$. To what depth should the water be poured into the beaker so that coin is again in focus? (Refractive index of water is $\frac{4}{3}$ )

When a plane mirror is rotated through an angle $\theta$ then the reflected ray turns through the angle $2\,\theta$ then the size of the image

An object is placed in front of a convex mirror of focal length $f$. Find the maximum and minimum distance of two object from the mirror such that the image is real and magnified.

A convergent lens of power 8D is used as a simple microscope. The magnification produced by the lens, when the final image is formed at least distance of distinct vision (i.e. 25 cm) is

When light waves suffer reflection at the interface between air and glass, the change of phase of the reflected wave is equal to

A real image is formed by a convex lens. If we put it in contact with a convave lens and the combination again forms a real image, which of the following is true for the new image from the combination:

A lens behaves as a converging lens in air and a diverging lens in water. The refractive index of the material is

A ray of light is incident at an angle of ${60^0}$ on one face of a prism of angle ${30^0}$. The ray emerging out of the prism makes an angle of ${30^0}$ with the incident ray. The emergent ray is

A leaf which contains only green pigments, is illuminated by a laser light of wavelength $0.632\,\,\mu m$. It would appear to be

A sunshine recorder globe of $30 \mathrm{~cm}$ diameter is made of glass of refractive index $\mu=1.5$. A ray enters the globe parallel to the axis. Find the position from the centre of the sphere where the ray crosses the axis.

For which colour, velocity of light is maximum in glass:

A converging lens is used to form an image on a screen. When upper half of the lens is covered by an opaque screen

A divergent lens will produce

If eye is kept at a depth $h$ inside water of refractive index and viewed outside, then the diameter of the circle through which the outer objects become visible, will be

A glass slab of thickness $8\;cm$ contains the same number of waves as $10\;cm$ of water when both are transverse by the same monochromatic light. If the refractive index of water is 4/3, then refractive index of glass is

When two thin lenses are in contact, their combined power is 9 D. when they are separated by a small distance of 20 cm, their equivalent power becomes $\frac{{27}}{5}\,\,D$.Their individual’s power (in dioptre) is

A thin equiconvex glass lens of refractive index
1.5 has power of 5 D. When the lens is immersed
in a liquid of refractive index $\mu,$ it acts as a
divergent lens of focal length 100 cm. The value
of $\mu$ of liquid is:

In a simple microscope, if the final image is located at infinity then its magnifying power is

When a glass lens with $n = 1.47$ is immersed in a trough of liquid, it looks to be disappeared. The liquid in the trough could be

A glass prism of refractive index $1.5$ and angle of prism $6^{\circ}$ is put in contact with another prism of refractive index $1.6$ when a ray of light is made incident on this combination normally then it emerges out undeviated. The angle of second prism will be-

The dispersion for a medium of wavelength $\lambda$ is $D$, then the dispersion for the wavelength $2\,\lambda$ will be

An astronomical telescope has a large aperture to

Total flux produced by a source of $1\,\,cd$is